Much Colder Air Moving In; Snow Next Week?

After a cold front moved through this evening, temperatures have begun to fall as colder air is ushered in from the north and west. That means it's time to say "goodbye" to the mild 50's we saw on Wednesday. By the time we wake up on Christmas Eve morning, temperatures will be roughly 25° cooler than what we saw Wednesday afternoon. However, it will still be an above average day in terms of low and high temperatures on Christmas Eve despite it being significantly cooler.


The cooler air will remain in place for Christmas Day with temperatures only expected around 41°. But, that is still above average in terms of temperatures. Rain moves in on Saturday with slightly milder air arriving, followed by a few flakes possible on Sunday.

Then, our eyes turn to Monday and Monday night, which is when another stronger storm system is expected to move into the Stateline from Texas. The low pressure associated with that system is expected to be rather strong as it moves northeastward towards the region. Therefore, plenty of moisture will likely be available. Here is the most likely scenario according to the forecast models as of tonight:

With a track like this, the low will be close enough to the region to draw in enough warm air to give the Stateline a mainly rain event. And that is typically the case with these winter season storm systems. The stronger they get, the more warm air they draw in. And the closer they are to the Stateline, the warmer we are. Therefore, with these winter season storms, we look for the lows to move across Southern Illinois into Central Indiana if we want sufficient cold air to support snowfall. With Monday's storm system, it looks like it will move slightly too far north to allow an accumulating snow to occur for much of the Northern Illinois and Southern Wisconsin region.

Now, there is a possibility that the models are overdoing the strength of the low, and therefore taking it too far north. This is the other potential track the low could take--and this track has been suggested by the models as well:

With a track more similar to this, there is a higher probability of seeing snowfall, which could accumulate. So it is a storm system that bears watching, especially because we have not seen much winter-like weather in December.